.left_panel {
    float: left;
    width: 200px;
    border: 1px solid blue;
    height: 700px;
}

.right_panel {
    float: left;
    width: 800px;
    border: 1px solid blue;
    height: 700px;
}

.small_img {
    width: 100px;
}

.large_img {
    width: 200px;
}